.....there has been a tremendous increase in the prevalence of allergic diseases such as asthma and food allergies in the last few decades. Recent evidence suggests that both alterations of microbial colonisation during the perinatal period and early-life exposure to environmental chemicals may promote dysregulated immune responses.  86,87,88  It therefore seems plausible that exposure to chemicals may affect the normal colonisation of the gut by bacteria, with effects on host physiology later in life. Therefore, chemical-induced perturbations of the composition of the GI microbiota may constitute an underestimated mechanism by which they interfere with human health.

From the study:

Pesticide Exposure - Glyphosate is the active component of Roundup (Montsanto, St Louis, MO, USA), the most widely used herbicide worldwide. It has been shown that the growth of Enterococcus faecalis bacteria isolated from cattle and horse faeces is inhibited by the lowest concentrations of glyphosate and the herbicide formulation tested.90 Further studies demonstrated that sensitivity to glyphosate is dependent on the bacterial strain. 

Mercury Exposure - In vivo, the importance of bacterial demethylation for the elimination of mercury has been confirmed in studies where the suppression or absence of the GI microbiota was associated with lower faecal excretion of total mercury 60,61,62 and with increased accumulation of mercury in most tissues, including the brain.......

Three types of "chemicals" often cited in Autism research and by parents are 1- Vaccines , 2- Pesticides and 3- Mercury

                                                                             YES, But What About AUTISM?

So we have ENVIRONMENTAL EXPOSURE, ENVIRONMENTAL POLLUTANTS, EXPOSURE TO CHEMICALS, CHEMICAL-INDUCED PERTURBATIONS OF THE GI MICROBIOTA, yet not one mention of Autism?

There is much information that should make the alarm LOUDER on the MICROBIOME and AUTISM:

•   changes in gut bacteria composition are reflected in changes in behaviors, highlighting a strong and interconnected way of communication between the gut microbiota and the brain.
•   dysfunctions of the gut bacteria-brain axis are correlated with several disorders: anxiety, depression, irritable bowel syndrome and, ABOVE ALL, AUTISM.
   
•   GI microorganisms have been known for decades to be involved in the biotransformation of xenobiotics (a foreign chemical substance found within an organism that is not normally naturally produced by or expected to be present within that organism.)  
  
•    About 50% of Desulfovibrio strains tested to date have the ability to produce MeHg. 
  
•    pyrosequencing analysis showed that gram-negative bacteria, Desulfovibrio and Bacteroides vulgatus, were detected at higher levels in autistic children

And from the very recent International Meeting for Autism Research (IMFAR): 

•    All of the daily stool samples from the child with autism contained four organisms that earlier research had associated with autism. These included Sarcina ventriculi, Barnesiella intestihominis, Clostridium bartlettii, and Clostridium bolteae. By contrast, none of these bacteria appeared in the stool of the unaffected sibling.
  
  
•   The bacterium Haemophilus parainfluenzae appeared in the stool of the child with autism during a three-day period when the child experienced GI pain, diarrhea and a spike in challenging behaviors including self-injury.
  
  
•   On a separate two-day period, another spike in H. parainfluenzae correlated with another increase in self-injurious behavior – but this time without any change in stool consistency or obvious signs of GI pain.
  
  
•    The appearance of H. parainfluenzae in the child’s stool came as a surprise to the researchers. This bacterium normally resides in the respiratory tract, where its overgrowth can cause ear, throat and lung infections. None of those sicknesses were present in the child or family members during the study period....                             
  

                                                   The Immune System and Microbiome are Connected

•    Other researchers have suggested a link between the gut–brain axis and neuropsychiatric disorders such as autism, depression, and eating disorders. The gut contains microorganisms that share a structural similarity with the neuropeptides involved in regulating behavior, mood, and emotion—a phenomenon known as molecular mimicry. The body can’t tell the difference between the structure of these mimics and its own cells, so antibodies could end up attacking both, potentially altering the physiology of the gut–brain axis. 
  
•  Microbiota interact with host cells in particular by modulating the mitochondrial activities. This mitochondria – microbiota cross-talk is intriguing because mitochondria and bacteria share a lot of common structural and functional features. Several studies reported strong association between microbiota quality and diversity and mitochondrial function. The mitochondrial production of Reactive Oxygen Species plays an important role during the innate immune response and inflammation and is often target by pathogenic bacteria. 
  
  
•   Children with AU have significantly reduced levels of plasma IgG and IgM compared to both DD and TD controls, suggesting an underlying defect in immune function. This reduction in specific Ig levels correlates with behavioral severity, where those patients with the highest scores in the behavioral battery have the most reduced levels of IgG and IgM.
  
•   When the body doesn't produce enough IgG, the condition is known as an IgG deficiency. People with IgG deficiency are more likely to get infections.
  
•    Patients are often referred to immunologists for the evaluation of reduced serum IgG levels. Because antibody deficiencies are the most common of the primary immune defects, examination of humoral immunity in these patients is valuable. 
  
•   Patients with profoundly reduced (<100 mg/dL) or significantly reduced (100–299 mg/dL) IgG levels with clearly impaired antibody response are generally treated with replacement immunoglobulin starting at 100 mg/kg per week given either intravenously or subcutaneously. 
  
•   Prophylactic antibiotics may also be required in some individuals. 

It's important to remember that Dan Olmsted reported on the profound recovery of a young child after receiving IVIG (replacement immunoglobulin):

"Absent, too, is the fact that Child 11 is now in college in California after graduating from high school with a 3.75 academic average.

The treatment the father cited, and the rationale for it, has been described in detail by the U.S. doctor who administered it. “A number of immunological abnormalities have been observed in patients with autism,” according to the text of comments he subsequently made at a meeting of an autism group. He said all the children he treated, which included child 11, had regressed after the MMR shot.

“Natural killer cells … that appear to play an important role in defense against virus infected cells and tumor cells are decreased both in numbers and functions in patients with autism. This deficiency may play a role in increased susceptibility to various infections that may in turn play a role in the pathogenesis of autism.”

He goes on to describe the use of IVIG in this context, at the 400 mg/kg dose the father cited. “IVIG has been used in a number of primiary immunodeficiency syndromes, and autoimmune and immunoinflammatory disorders including demyelinating polyneuropathy, multiple sclerosis, Guillain-Barre syndrome."

Many children with an Autism diagnosis need immune therapies and families are not aware of this important fact.  A big reason we are seeing so many children with both AUTISM and PANDAS, PANS, and Lyme diagnoses may be that something has happened to alter their Microbiome, thus their immune system.  More must be done to help our very sick and affected children.  In that theme, stay tuned next time for an update on Fecal Transplants.

Teresa Conrick is Contributing Editor to Age of Autism.